OBJECTIVE: To analyse the influence of mitochondrial DNA (mtDNA) haplogroups on serum levels of molecular biomarkers in patients with osteoarthritis (OA). METHODS: Serum levels of molecular biomarkers of cartilage metabolism (collagen type II markers: C-terminal neoepitope generated by the collagenase-mediated cleavage of collagen type II triple helix (C2C), collagen type II (Coll2-1, and its nitrated form, Coll2-1NO(2)), procollagen type II (CPII)), synovial metabolism (hyaluronic acid (HA)) and cartilage and synovial turnover (cartilage glycoprotein 39 (YKL-40)) were analysed in 73 patients with OA and 77 healthy controls using ELISAs. All participants had been previously genotyped for the mtDNA haplogroups J, U and H. Non-parametric and multivariate analysis were performed to test the effects of the clinical variables, including gender, age, smoking status, diagnosis, mtDNA haplogroups and radiological Kellgren and Lawrence (K/L) grade on the serum levels of the molecular markers. RESULTS: Non-parametric analysis found increased serum levels of HA in patients with OA, while the values for C2C and the C2C/CPII ratio were significantly higher in the healthy controls. A multiple regression analysis showed a relationship between the mtDNA haplogroups and serum levels of the typical collagen type II markers. Carriers of the mtDNA haplogroup H had higher levels while carriers of the mtDNA haplogroup J showed lower levels. Statistically significant interactions between mtDNA haplogroups and diagnosis and between mtDNA haplogroups and radiological K/L grade in the serum levels of molecular markers were also found. CONCLUSION: A new role for mtDNA haplogroups emerges from this work. The results suggest that the mtDNA haplogroups interact significantly with the serum levels of OA-related molecular markers, suggesting the possibility of their use as a complementary assay with these molecular markers. [less ▲]

OBJECTIVE: A major barrier inhibiting the discovery of structural modifying agents for osteoarthritis (OA) is an incomplete understanding of early disease events. Herein, we investigated the time course ... [more ▼]

OBJECTIVE: A major barrier inhibiting the discovery of structural modifying agents for osteoarthritis (OA) is an incomplete understanding of early disease events. Herein, we investigated the time course of collagen II cleavage and fibril disruption in the well-validated Hartley guinea pig model of spontaneous OA of the knee. METHODS: Knee joints of 46 male Hartley guinea pigs were analyzed at 3 weeks, 2, 4, 7, 10, 12, and 18 months of age for histological severity of OA, cartilage collagen fibril disruption by semi-quantitative polarized light microscopy, and expression of type II collagen degradation biomarkers, 9A4 and Coll2-1, by immunohistochemistry. In addition, serum biomarkers specific for collagen II degradation, CTX-II, C2C, and Coll2-1 were quantified. RESULTS: Collagen fibril disruption and expression of the collagenase-generated cleavage neoepitope, 9A4, were observed as early as 2 months of age, despite the appearance of histological OA at 4 months of age. Only serum Coll2-1 increased coincident with the early disruption of the collagen fibril between 3 weeks and 7 months, in contrast to serum C2C, which did not change significantly or correlate with histological severity. Inversely, CTX-II declined dramatically from 3 weeks to 4 months and remaining low thereafter, coincident with growth plate turnover. CONCLUSIONS: Collagenase cleavage and disruption of the type II collagen network are early OA disease events in this model, preceding histological evidence of proteoglycan loss. The markedly different serum profiles of collagen II-related biomarkers during the early stages of disease development suggest compartmental segregation and temporal regulation of collagen degrading enzymes. [less ▲]

OBJECTIVE: To determine the effects of iron depletion on serum levels of joint biomarkers and on joint symptoms in patients with hereditary haemochromatosis (HH). METHODS: Levels of biomarkers were ... [more ▼]

OBJECTIVE: To determine the effects of iron depletion on serum levels of joint biomarkers and on joint symptoms in patients with hereditary haemochromatosis (HH). METHODS: Levels of biomarkers were measured in 18 patients with HH at the time of diagnosis and after iron depletion. The markers were type II collagen degradation (Coll2-1) and its nitrated form (Coll2-1NO(2)), type II procollagen synthesis (CPII), MPO, COMP and HA. For each patient, demographic data were collected and the global joint pain (visual analogue scale) was assessed before and after iron depletion by phlebotomy. RESULTS: A total of 18 patients [10 males; mean (s.d.) age 48 (11) years] were homozygous for the C282Y mutation. No patient had liver dysfunction. Ferritin level before iron removal was 627.5 (range 133-3276) microg/l, and duration of the iron depletion phase was 295 (70-670) days. Serum levels of both Coll2-1 and CPII were significantly increased from diagnosis after iron depletion: 80.1 (55.6-113.5) vs 96.0 (48.8-136.3) nM (P = 0.004) and 731.4 (374.2-1012.3) vs 812.8 (535.8-1165.6) ng/ml (P = 0.03), respectively. Levels of other biomarkers were not modified by iron depletion. Ferritin level, which at baseline was correlated with body iron store (r = 0.63; P = 0.008), was significantly correlated with HA level measured before iron depletion (r = 0.60; P = 0.01). Global joint pain was not correlated with ferritin concentration and did not significantly decrease after iron depletion: 43 (19-73) vs 36 (16-67) mm (P = 0.07). CONCLUSIONS: In patients with HH, cartilage homoeostasis is modified by iron excess and an increase in type II collagen turnover occurs after excess iron removal. [less ▲]

Establishing the osteoarticular status of the horse is often performed by means of radiological screening of the animals. Widespread blood sampling could reveal to be an interesting alternative to this ... [more ▼]

Establishing the osteoarticular status of the horse is often performed by means of radiological screening of the animals. Widespread blood sampling could reveal to be an interesting alternative to this procedure which is time consuming and sometimes technically difficult. The aim of this study was to investigate the relationship between the radiological status of the horses and the levels of biochemical markers of cartilage degradation and synovial inflammation. A specific radiological scoring and classification system was therefore developed and applied on 63 stallions presented for studbook admission. Additionally, groups of horses were established according to the occurrence of osteochondrosis, degenerative joint disease and distal interphalangeal joint effusion. Insulin growth factor-I, myeloperoxidases, Coll2-1 and Coll2-1NO(2) were used as blood markers. The combination of the blood parameters did not seem to correlate with the used scoring system. Coll2-1NO(2) levels however tended to increase with poorer radiological class and this could therefore potentially be a useful predictor of the osteoarticular status in the horse. Coll2-1 levels were significantly higher in the degenerative joint disease group. A high percentage of horses with distal interphalangeal joint effusion was present in this study and was associated with decreased IGF-I and increased Coll2-1 levels. [less ▲]

Collagens are major constituents of connective tissues in the animal kingdom. During aging and inflammatory-related diseases, the collagen network undergoes oxidation that leads to structural and ... [more ▼]

Collagens are major constituents of connective tissues in the animal kingdom. During aging and inflammatory-related diseases, the collagen network undergoes oxidation that leads to structural and biochemical alterations within the collagen molecule. Collagen oxidation appears to be a key determinant of aging and a critical physiopathologic mechanism of numerous diseases. Further, the detection of oxidized-collagen peptides seems to be a promising approach for the diagnosis and the prognosis of inflammatory diseases. This chapter reviews the structural and biochemical changes to collagen induced by reactive oxygen and nitrogen species and discusses recent data on the use of collagen-derived biomarkers for measuring oxidative damage. [less ▲]

OBJECTIVES: To determine Coll2-1, Coll2-1NO(2) and myeloperoxydase (MPO) levels in serum of patients with knee or hip osteoarthritis (OA) before the surgery, 3 months and 1 year after knee or hip ... [more ▼]

OBJECTIVES: To determine Coll2-1, Coll2-1NO(2) and myeloperoxydase (MPO) levels in serum of patients with knee or hip osteoarthritis (OA) before the surgery, 3 months and 1 year after knee or hip replacement. METHODS: Coll2-1, Coll2-1NO(2) and MPO were measured in 103 patients with isolated symptomatic knee or hip OA candidates for joint replacement. Sera were taken the day before surgery, 3 months and 1 year after hip or knee replacement. Coll2-1 and Coll2-1NO(2) immunohistochemistry was performed on biopsies removed from cartilage lesions. RESULTS: Immunostainings revealed the extensive presence of Coll2-1 and Coll2-1NO(2) in the superficial layer of fibrillated cartilage and around some chondrocytes clusters. Three months after joint replacement, Coll2-1 and MPO serum levels were decreased and even reached the reference value for Coll2-1. By contrast, Coll2-1NO(2) levels remained elevated. At 1-year follow-up, Coll2-1 levels remained at the reference value, MPO levels were similar to those measured at 3 months, and Coll2-1NO(2) levels were unchanged and comparable to the pre-surgery values. However, in patients with pre-surgery values above the median (more than 0.42 nM), Coll2-1NO(2) levels significantly and progressively decreased post-operatively, but tended towards an increase in patients with pre-surgery Coll2-1NO(2) values below the median. CONCLUSIONS: The normalisation of Coll2-1 levels 3 months after surgery indicates that Coll2-1 is a disease-specific marker that is sensitive to the structural changes occurring in a single joint. Furthermore, the immunohistochemical findings are consistent with the concept that the major source of serum Coll2-1 is the damaged articular cartilage. Finally, serum MPO levels decreased after joint replacement indicating that neutrophil activation occurs in OA joints, even in the late stage of the disease. [less ▲]